1. Technical Field
The present invention relates to a traveling wave slot antenna and a method of making it. The invention more particularly relates to a traveling wave slot antenna, which has a broad frequency band width and which has a low profile configuration to enable it to be mounted, for example, in the outer skin of aircraft as well as many other applications.
2. Background Art
Printed circuit antennae have been known as narrow band elements since the 1960's. Elements making up such an antenna usually take the form of a planar structure with a conductive plate suspended above a ground plane fed at one or more feed points. See, for example, U.S. Pat. No. 5,748,152, which is incorporated herein by reference.
These elements have been used in many applications with wide variations in characteristics. Generally, such an antenna is intended to radiate normal to the ground plane surface to which they are mounted. The antenna elements are commonly fabricated using photolithography techniques on printed circuit board materials. Such techniques allow for very accurate reproduction of the elements in large quantities. These antenna are easily combined into arrays for use at microwave frequencies for communication, Radar and sensing applications.
The U.S. Pat. No. 5,748,152 discloses a slot notch antenna which is generally planar in configuration and has a pair of diverging slot sections terminating in an aperture. The planar antenna is positioned within an open top enclosure above a flat base ground plane. Such a configuration is inherently lossy, and thus not sufficiently efficient for many applications.
While such an antenna may be satisfactory for some applications, it would be highly desirable to have such a low-cost, low profile high bandwidth antenna, which has significantly improved radiation efficiency.